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Restoring Sonoma County Tidal Zone

Derek Moore, THE PRESS DEMOCRAT
February 16, 2012

Officials give a tour of the Sears Point Ranch project
Sonoma Land Trust and National Oceanic and Atmospheric Administration officials give a tour of the Sears Point Ranch project to Japanese scientists on Wednesday. The 2,327-acre site extends from Infineon Raceway to the bay. Farmland near the bay — the green swath in the middle of the picture — will be flooded and restored as a tidal wetland. —John Burgess / PD

One of the nation’s most ambitious tidal restoration projects is nearing the start of construction at Sears Point south of Sonoma, six years after plans to build a casino at the site sparked efforts to protect the land from development.

Sears Point Ranch spans 2,327 acres from San Pablo Bay across Highway 37 and up the hillside on the east side of Lakeville Highway near Infineon Raceway.

The land currently is used for cattle grazing and as the location of a hunting club, but over the years was the proposed site for developments ranging from an airport to a casino.

The Sonoma Land Trust had a different vision in mind after it acquired the property in 2005. That includes turning 1,000 acres into a tidal marsh that on a map looks the outline of a giant fish.

The work is designed to improve the environment and also protect Highway 37 and a railroad from surging storm waters.

“You get a big storm, and the water is lapping at the road,” said project manager Julian Meisler.

A group that included project managers and two visiting scientists from Japan stood on a levee Wednesday where work on the marsh restoration is set to begin this summer.

The group looked down on farmland that as a result of reclamation efforts that began in the mid-19th century exposed the peaty soil and sank the land to below sea level.

The restoration includes elevating the existing farmland by about eight feet. Rather than spend money to truck the dirt in, project managers will instead rely on a more natural process that Meisler said has never been tried before on a project of this size.

The plans call for installing marsh plants and hundreds of small islands to create wind breaks and filter out sediment from the incoming tides. Whether that will result in enough sediment to keep pace with the expected rise in sea level remains to be seen.

Existing levees will be breached to allow tidal waters to enter the marsh area. The group also plans to build a new levee to protect the railroad, highway and adjacent private property.

The Japanese scientists wanted a first-hand look at the project for ideas on how to combine flood control with environmental conservation, after a tsunami last year in their country highlighted such concerns.

“We don’t have any technical guidelines right now,” said Kunihiko Amano, head of the River Environment Division at Japan’s National Institute for Land and Infrastructure Management.

Sears Point is the largest restoration and preservation project along the shores of San Francisco Bay since the purchase of 16,596 acres of Cargill Salt production facilities in the South Bay in 2002.

Meisler said the land trust raised $20 million to acquire the Sears Point property in 2005 and expects to spend $18 million to complete the restoration work. He said much of that money will come from state and federal grants.

The remaining 1,300 acres or so will be maintained as grazing fields and open space.

The finished project also will include a four-mile extension of the San Francisco Bay Trail, enabling hikers and bikers to travel from the Petaluma River to Tolay Creek.